New Delhi: Prime Minister Narendra Modi is set to address a rally in Mathura on Monday to mark the first anniversary of National Democratic Alliance (NDA) government at the Centre. PM Modi is likely to announce implementation of the One Rank One Pension (OROP) scheme for ex-servicemen.

Defence Ministry sources on Sunday said modalities relating to the long-pending demand of ex-servicemen have been thrashed out.

Finance Minister Arun Jaitley had said on Friday that the OROP concept was "an unambiguous commitment" of the government and it will be implemented. He said the Defence Ministry is in talks with various stakeholders on the methodology of calculation of pension concerning ex-servicemen.

OROP relates to payment of uniform pension to defence forces personnel retiring in the same rank with the same length of service, irrespective of their date of retirement. The government had told the Parliament earlier this year that the principle of OROP for the armed forces has been accepted and it will be implemented once the modalities are approved by the government.

Meanwhile, Laxmikant Bajpai, the BJP's Uttar Pradesh unit president and his senior colleagues visited the rally venue and reviewed the arrangements. BJP leader Deen Dayal Dham said the venue will accommodate over one lakh people.

"TV screens are being installed so that people can see and hear the Prime Minister. The rally will be telecast live to over 130 countries," a BJP leader said. PM Modi, who will arrive in Mathura at 3.45 pm on Monday, will spend some time at the memorial of Bharatiya Jana Sangh leader Deen Dayal Upadhyaya. He will leave for Delhi later in the day.

Meantime, a police officer said a letter had been received at the Mathura SSP's office threatening an explosion at the rally ground. A man whose brother allegedly sent an SMS to a journalist was arrested on Saturday night, police said.